Incorporation of Thymine Nucleotides by DNA Polymerases through T–HgII–T Base Pairing



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A dangerous matchmaker: In the presence of HgII ions, DNA polymerases incorporated thymidine 5′-triphosphate (TTP) at the site opposite thymine in a template strand and made a phosphodiester bond to elongate the primer strand. This unusual metal-mediated base pair was recognized by the DNA polymerases, which went on to synthesize the full-length product (see picture).